kernel/linux.git/drivers/mmc/core/queue.h, branch v4.14.263

mmc: block: Delete mmc_access_rpmb()

2020-01-12T11:12:03+00:00

commit 14f4ca7e4d2825f9f71e22905ae177b899959f1d upstream. This function is used by the block layer queue to bail out of requests if the current request is towards an RPMB "block device". This was done to avoid boot time scanning of this "block device" which was never really a block device, thus duct-taping over the fact that it was badly engineered. This problem is now gone as we removed the offending RPMB block device in another patch and replaced it with a character device. Cc: Tomas Winkler Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson Cc: Jisheng Zhang Signed-off-by: Greg Kroah-Hartman

mmc: block: Convert RPMB to a character device

2020-01-12T11:12:03+00:00

commit 97548575bef38abd06690a5a6f6816200c7e77f7 upstream. The RPMB partition on the eMMC devices is a special area used for storing cryptographically safe information signed by a special secret key. To write and read records from this special area, authentication is needed. The RPMB area is *only* and *exclusively* accessed using ioctl():s from userspace. It is not really a block device, as blocks cannot be read or written from the device, also the signed chunks that can be stored on the RPMB are actually 256 bytes, not 512 making a block device a real bad fit. Currently the RPMB partition spawns a separate block device named /dev/mmcblkNrpmb for each device with an RPMB partition, including the creation of a block queue with its own kernel thread and all overhead associated with this. On the Ux500 HREFv60 platform, for example, the two eMMCs means that two block queues with separate threads are created for no use whatsoever. I have concluded that this block device design for RPMB is actually pretty wrong. The RPMB area should have been designed to be accessed from /dev/mmcblkN directly, using ioctl()s on the main block device. It is however way too late to change that, since userspace expects to open an RPMB device in /dev/mmcblkNrpmb and we cannot break userspace. This patch tries to amend the situation using the following strategy: - Stop creating a block device for the RPMB partition/area - Instead create a custom, dynamic character device with the same name. - Make this new character device support exactly the same set of ioctl()s as the old block device. - Wrap the requests back to the same ioctl() handlers, but issue them on the block queue of the main partition/area, i.e. /dev/mmcblkN We need to create a special "rpmb" bus type in order to get udev and/or busybox hot/coldplug to instantiate the device node properly. Before the patch, this appears in 'ps aux': 101 root 0:00 [mmcqd/2rpmb] 123 root 0:00 [mmcqd/3rpmb] After applying the patch these surplus block queue threads are gone, but RPMB is as usable as ever using the userspace MMC tools, such as 'mmc rpmb read-counter'. We get instead those dynamice devices in /dev: brw-rw---- 1 root root 179, 0 Jan 1 2000 mmcblk0 brw-rw---- 1 root root 179, 1 Jan 1 2000 mmcblk0p1 brw-rw---- 1 root root 179, 2 Jan 1 2000 mmcblk0p2 brw-rw---- 1 root root 179, 5 Jan 1 2000 mmcblk0p5 brw-rw---- 1 root root 179, 8 Jan 1 2000 mmcblk2 brw-rw---- 1 root root 179, 16 Jan 1 2000 mmcblk2boot0 brw-rw---- 1 root root 179, 24 Jan 1 2000 mmcblk2boot1 crw-rw---- 1 root root 248, 0 Jan 1 2000 mmcblk2rpmb brw-rw---- 1 root root 179, 32 Jan 1 2000 mmcblk3 brw-rw---- 1 root root 179, 40 Jan 1 2000 mmcblk3boot0 brw-rw---- 1 root root 179, 48 Jan 1 2000 mmcblk3boot1 brw-rw---- 1 root root 179, 33 Jan 1 2000 mmcblk3p1 crw-rw---- 1 root root 248, 1 Jan 1 2000 mmcblk3rpmb Notice the (248,0) and (248,1) character devices for RPMB. Cc: Tomas Winkler Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson Cc: Jisheng Zhang Signed-off-by: Greg Kroah-Hartman

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

mmc: Delete bounce buffer handling

2017-10-04T08:22:55+00:00

In may, Steven sent a patch deleting the bounce buffer handling and the CONFIG_MMC_BLOCK_BOUNCE option. I chose the less invasive path of making it a runtime config option, and we merged that successfully for kernel v4.12. The code is however just standing in the way and taking up space for seemingly no gain on any systems in wide use today. Pierre says the code was there to improve speed on TI SDHCI controllers on certain HP laptops and possibly some Ricoh controllers as well. Early SDHCI controllers lacked the scatter-gather feature, which made software bounce buffers a significant speed boost. We are clearly talking about the list of SDHCI PCI-based MMC/SD card readers found in the pci_ids[] list in drivers/mmc/host/sdhci-pci-core.c. The TI SDHCI derivative is not supported by the upstream kernel. This leaves the Ricoh. What we can however notice is that the x86 defconfigs in the kernel did not enable CONFIG_MMC_BLOCK_BOUNCE option, which means that any such laptop would have to have a custom configured kernel to actually take advantage of this bounce buffer speed-up. It simply seems like there was a speed optimization for the Ricoh controllers that noone was using. (I have not checked the distro defconfigs but I am pretty sure the situation is the same there.) Bounce buffers increased performance on the OMAP HSMMC at one point, and was part of the original submission in commit a45c6cb81647 ("[ARM] 5369/1: omap mmc: Add new omap hsmmc controller for 2430 and 34xx, v3") This optimization was removed in commit 0ccd76d4c236 ("omap_hsmmc: Implement scatter-gather emulation") which found that scatter-gather emulation provided even better performance. The same was introduced for SDHCI in commit 2134a922c6e7 ("sdhci: scatter-gather (ADMA) support") I am pretty positively convinced that software scatter-gather emulation will do for any host controller what the bounce buffers were doing. Essentially, the bounce buffer was a reimplementation of software scatter-gather-emulation in the MMC subsystem, and it should be done away with. Cc: Pierre Ossman Cc: Juha Yrjola Cc: Steven J. Hill Cc: Shawn Lin Cc: Adrian Hunter Suggested-by: Steven J. Hill Suggested-by: Shawn Lin Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: debugfs: Move block debugfs into block module

2017-08-30T13:03:39+00:00

If we don't have the block layer enabled, we do not present card status and extcsd in the debugfs. Debugfs is not ABI, and maintaining files of no relevance for non-block devices comes at a high maintenance cost if we shall support it with the block layer compiled out. The debugfs entries suffer from all the same starvation issues as the other userspace things, under e.g. a heavy dd operation. The expected number of debugfs users utilizing these two debugfs files is already low as there is an ioctl() to get the same information using the mmc-tools, and of these few users the expected number of people using it on SDIO or combo cards are expected to be zero. It is therefore logical to move this over to the block layer when it is enabled, using the new custom requests and issue it using the block request queue. On the other hand it moves some debugfs code from debugfs.c and into block.c. Tested during heavy dd load by cat:in the status file. Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: Anonymize the drv op data pointer

2017-08-30T13:03:38+00:00

We have a data pointer for the ioctl() data, but we need to pass other data along with the DRV_OP:s, so make this a void * so it can be reused. Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: Move boot partition locking into a driver op

2017-06-20T08:30:26+00:00

This moves the boot partition lock command (issued from sysfs) into a custom block layer request, just like the ioctl()s, getting rid of yet another instance of mmc_get_card(). Since we now have two operations issuing special DRV_OP's, we rename the result variable ->drv_op_result. Tested by locking the boot partition from userspace: > cd /sys/devices/platform/soc/80114000.sdi4_per2/mmc_host/mmc3/ mmc3:0001/block/mmcblk3/mmcblk3boot0 > echo 1 > ro_lock_until_next_power_on [ 178.645324] mmcblk3boot1: Locking boot partition ro until next power on [ 178.652221] mmcblk3boot0: Locking boot partition ro until next power on Also tested this with a huge dd job in the background: it is now possible to lock the boot partitions on the card even under heavy I/O. Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: Tag DRV_OPs with a driver operation type

2017-06-20T08:30:25+00:00

We will expand the DRV_OP usage, so we need to know which operation we're performing. Tag the operations with an enum:ed type and rename the function so it is clear that it deals with any command and put a switch statement in it. Currently only ioctls are supported. Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: remove req back pointer

2017-06-20T08:30:24+00:00

Just as we can use blk_mq_rq_from_pdu() to get the per-request tag we can use blk_mq_rq_to_pdu() to get a request from a tag. Introduce a static inline helper so we are on the clear what is happening. Suggested-by: Christoph Hellwig Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: queue: delete mmc_req_is_special()

2017-06-20T08:30:19+00:00

commit cdf8a6fb48882651049e468e6b16956fb83db86c "mmc: block: Introduce queue semantics" deleted the last user of mmc_req_is_special() and it was a horrible hack to classify requests as "special" or "not special" to begin with, so delete the helper. Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson